Method for providing precisely controlled edge on sheet material and apparatus therefor



United States Patent Inventor Appl. No. Filed Patented Assignee METHODFOR PROVIDING PRECISELY CONTROLLED EDGE ON SHEET MATERIAL AND APPARATUSTHEREFOR 21 Claims, 7 Drawing Figs.

0.8. CI Int. Cl B26d 104 Field of Search. 83/368,

References Cited UNITED STATES PATENTS 4/1919 Hazeltine PrimaryExaminer-James M. Meister Atlorney- Peter L. Costas ABSTRACT: There isdisclosed a method for providing embossed sheet material with at leastone edge in predetermined alignment with respect to the embossments byfirst embossing the sheet material with a longitudinally extending ribin one side marginal portion. Supported on the sheet material is a guidemember with a groove receiving the rib which controls cutting means andthe guide member tracks with the sheet material so as to cut the sheetmaterial in a predetermined location across the width thereof relativeto the rib. The apparatus for performing the method includes a rotatablymounted cutting roll desirably provided with a cutting groove thereinreceiving the cutting means and the cutting roll is preferablyadjustable axially to ensure proper alignment between the cutting meansand the cutting groove.

EDGE ON SHEET MATERIAL AND APPARATUS THEREFOR BACKGROUND OF THEINVENTION Synthetic plastic sheet materials embossed withsemicylindrical ribs and semispherical or parabolic formations are beingused widely for providing optical effects in many applications. Byreason of the tendency for such embossments to focus the light rayspassing therethrough at various points depending upon theangle ofincidence, relative movement between the viewer and an articleemployingsuch embossed sheet material can provide various interesting opticaleffects. One extensive application for the cylindrical rib material isthe manufacture of cards and other printed materials useful for signs,point of sales displays, greeting cards and decorative accents.

A pattern of printing or a design is provided on the surface of thesheet material opposite that having the cylindrical lenses and is sodevised as to comprise two distinct images. The printed image may beprinted directly upon the opposite surface of the synthetic plasticsheet material or upon another substrate which is. then bonded to thesynthetic plastic sheet material. Upon viewingfrom one direction, one ofthe two images is seen but as relative movement between the viewer andthe printed article occurs, the second image replaces the first due tothe variation in the angle of viewing. Exemplary of this type ofstructure is the disclosure of Lemelson U.S. Pat. No, 3,026,648.

More recently, there have been very significant efforts to obtainthree-dimensional effects in printed items such as greeting cards,photographs and the like and these have basically made application ofthe principles hereinbefore described. Exemplary of the structures whichhave required highly accurate alinement is the disclosure of Rice et al.U.S.-

Pat. No. 3,241,429, granted Mar. 22, 1966.

In attempting to utilize continuously embossed synthetic plastic sheetmaterial in articles which require precise alinement between printedpatterns and embossed lenses, difficulties will generally be encounteredsince the process of extrusion and embossing produces variations in thewidth of the sheet material. More particularly, in order to maintain theregular spacing of the embossments on the plastic sheet from one sidemargin to the other, when the plastic is still. at an elevatedtemperature and relatively soft as it is being stripped from theembossing roll, the sheet material must normally be considerably widerthan the intended width of the finished sheet material. Because thesheet is being drawn over the surface of the embossing roll. it is undersome tension and there is a tendency for the heated material to elongateand narrow in width as it cools and hardens. This condition is morepronounced in the side marginal portions of the sheet material so thatif a distortion-free product is desired, it has been customary to trimthe side marginal portions and retain the principal body portion whereinthe embossments are generally undistorted.

However, when such sheet material is trimmed, the deviation ordistortion of the side marginal portions makes it most difficult toensure precise alinement of the trimmed side edges with the embossmentsin the principal portion of the sheet material. For those applicationswhere precise alinement or registry is required, as when the materialitself is to beprinted or when the material is to be laminated with aprinted substrate, this deviation presents most significant problems.

It is an object of the present invention to provide a method wherebyembossed sheet material may be trimmed in the side marginal portionsthereof to provide a side edge which is in predetermined alinement withthe embossments in the principal portion thereof.

It is also an object to provide such a method which is readily adaptedto deviation'in the width of the sheet material and which will readilyaccommodate'displacement of the sheet material axially along the surfaceof a support roll.

Another object is to provide such a method wherein there may beaccommodated deviations in thickness of the sheet material occurring bypulsation of the extruder or irregularities in the embossing operation.

A further object is to provide relatively simple yet highly effectiveapparatus for precisely trimming the side margin of embossed sheetmaterial so as to provide a side edge in predetermined alinement withembossments in the principal portion of the sheet material.

SUMMARY OF THE INVENTION It has now been found that the foregoing andrelated objects can be readily attained by a method in which a length ofplastic material is embossed with at least one rib extendinglongitudinally of the sheet material in at least one side marginalportion thereof and with embossments of desired configuration in theprincipal portion between the side marginal portions thereof. A guidemember is supported on the sheet material and controls cutting meansadapted to cut the sheet material as it passes thereby. The guide memberhas a groove in one surface thereof receiving the rib on the sheetmaterial and is supported at a cutting station so as to be movable totrack in the direction extending transversely of the path of movement ofthe sheet material.

The embossed sheet material is passed through the station with the ribthereof being received in the groove of the guide member and with theguide member tracking transversely of the direction of the path ofmovement of the sheet material in response to movement of the sheetmaterial in this direction. As the sheet material passes through thestation, the cutting means operates to cut the side marginal portion ofthe sheet material at a predetermined location across the width thereofrelative to the rib. Thereafter, the trimmed side marginal portion isseparated from the principal portion of the sheet material to provide anedge of predetermined alinement and spacing with respect to theembossments in the principal portion thereof.

As will be readily appreciated, the preferred embodiment of the presentinvention utilizes ribs in both side marginal portions of the sheetmaterial and guide means with associated cutting means to trim both sidemargins as the material passes through the cutting station. Inaccordance with one aspect, the cutting means is a simple cutting bladecarried by the guide member and extending into a cooperating groove in aroll over which the sheet material is passing.

More particularly, the apparatus of the present invention incorporates aroll assembly including a rotatably mounted cutting roll and providingfor passage of the sheet material about a substantial portion of theperiphery of the cutting roll. A guide member support means is mountedfor movement axially of the cutting roll and a guide member on the guidemember support means overlies the cutting roll and has at least onegroove therein adapted to receive a longitudinally extending rib on thesheet material passing about the periphery of the cutting roll. Theguide member controls cutting means adapted to cut the sheet material ata predetermined location across the length thereof relative to thegroove. lnoperation of the apparatus, the guide member support means maymove axially of the roll in response to axial displacement of the sheetmaterial along the surface of the cutting roll. Thus, necking in ordrift of the sheet material may be readily compensated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a semidiagrammaticillustration of apparatus embodying the present invention and showingthe path of synthetic plastic sheet material passing therethrough insolid line and of trimmed material in broken line;

FIG. 2 is an enlarged view of a portion of the apparatusof FIG. 1 insection intermediate along the length of the rolls;

FIG. 3 is a fragmentary perspective view of a portion of the apparatusof FIG. 1 to an enlarged scale;

FIG. 4 is a fragmentary plan view to an enlarged scale of the cuttingroll portion of apparatus of FIG. 1;

FIG. 5 is a perspective view of the guide block and guide block supportsubassembly of the apparatus to a greatly enlarged scale;

FIG. 6 is a partially diagrammatic fragmentary sectional view to agreatly enlarged scale showing the guide block, cutting blade andcutting roll in operation with a sheet of material passing therethrough;and

FIG. 7 is a fragmentary perspective view to an enlarged scale ofembossed synthetic plastic sheet material of the type used in thepresent invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Turning now indetail to the attached drawings, therein is illustrated apparatusembodying the present invention for cutting synthetic plastic sheetmaterial generally designated by the numeral 10 and which formed byextrusion of molten metal from the fragmentarily illustrated extruder 2into the nip between the embossing roll 4 and the back up roll 6. Oneconfiguration for the sheet material 10 in this embodiment is best seenin FIGS. 6 and 7 wherein the upper surface is provided withlongitudinally extending ribs 12 of triangular cross section in the sidemarginal portions thereof and with longitudinally extending ribs 14 ofsemicircular cross section in the principal portion thereof.

On the support posts 16 is a base member 18 which has mounted thereon aroll assembly generally designated by the numeral 20 and a slitterassembly generally designated by the numeral 22. The fasteners 24 securethe base portions of the roll mounting frame 26 and the slitter supportframe 28 to the base member 18, and the frames 26, 28 have spaced apart,upstanding sidewalls 30, 32 respectively, between which the sheetmaterial 10 may pass. The sidewalls 30 of the roll assembly 20 supporttherein the shafts 34 of three rolls 36, 38 and 40 arranged in atriangular cluster, and a guide element 42 with arcuate faces adjacentthe surfaces of the rolls 36, 38, 40 is disposed therebetween.

The sidewalls 32 of the slitter mounting frame 28 are stabilized attheir upper end by the tie bar 44 extending therebetween and support theshafts 46, 48 which have their axes lying in a common plane extendingnormally to the base member 18. Slidably mounted on the shafts 46, 48are slide blocks 50, 52 which secured thereto by fasteners 54 the slidesupport members 56, 58 which have an undercut slideway or key way (notshown) in the lower portion of the face thereof spaced from the blocks50, 52. The pressure between the bushings 60 in the slide blocks 50, 52and the shafts 46, 48 may be varied by the thumb screws 62.

Mounted in the slideway of the slide support members 56, 58 are slides64, 66 which have cooperating keys (not shown) formed thereon, and theslides 64, 66 may be adjusted along the length of the keyways by theadjusting screws 68 which have their lower ends journaled in the upperends thereof. The screws 68 are threadably received in an aperture inthe upper portion of the slide support members 56, 58 so that uponrotation of the handles 70 thereon, the slides 64, 68 will be movedalong the length of the keyways to vary their position vertic'ally.

Mounted on the slides 64, 66 by the fasteners 72 adjacent the lower endthereof are link connecters 74 and adjacent the upper end thereof arethe guide arms 76 which are of sufficient length to project over theroll 38. Elongated connecting links 78 are pivotably mounted at one endin the link connecters 74 by the pins 80 and have pivotably mounted atthe other end thereof by the pins 82 the guide block supports 84. Asbest seen in FIGS. 5 and 6, the guide block supports 84 have mountedthereon by the fasteners 86 the guide blocks 88, and by the fasteners 90the cutting blade holders 92 which in turn carry the cutting blades 94extending downwardly therefrom through the sheet material 10 and into acircumferential groove 96 in the roll 38.

The guide block supports 84 and thereby the guide blocks 88 and thecutting blades 94 are biased against the periphery of the roll 38 by thespring 98 which is disposed about the bolt 100 and serves to bias theguide block supports 94 downwardly aboutthe pivot pins 82. The pressureexerted by the spring 98 may be adjusted by varying the length of thebolt 100 between the guide block support 84 and guide arms 76. As can beseen, the bolt 100 is pivoted at its lower end in the guide blocksupport 84 and extends through the guide arms 76 with adjusting nuts102, 104 threadably engaged with the upper end thereof. Theadjustment ofthe length of the bolt 100 projecting above the guide arm 76 will varythe amount that the guide block support 84 is pivoted upwardly towardthe guide arms 76 and thereby the initial compression of the spring 98.Thus, the pressure which must be exerted against the bottom surface ofthe guide blocks 88 during operation to effect deflection or pivotingthereof relative to the guide arms 76 can be varied to maintain theblocks 88in firm surface contact despite variations in thickness of thesheet material 10.

Turning now to FIG. 4, the roll 38 may be moved axially between thesidewalls 30 of the roll mounting frame 26 to maintain the cuttingblades 94 in alinement with the groove 96 therein by the apparatus showntherein, The shaft 34 of the roll 38 has a collar 106 adjacent theinside surface of one of the sidewalls 30 and a shaft adapter 108 on theend thereof outwardly of the sidewall 30. A yoke 110 supported on thesidewall 30 has an aperture therein which threadably receives theadjusting screw 112, and the axial disposition of the roll may thus bevaried by rotation of the handle 114 to move the adjusting screw 112within the aperture of the yoke 110. The inner end of the adjustingscrew 112 has a bearing 116 of larger diameter which is secured thereonby the fastener 117 and which is rotatably seated within the shaftadapter 108 and held against axial movement outwardly therefrom by theengagement of the bearing 116 against the shoulder 119.

In operation of the apparatus, the length of sheet material 10 issuingfrom the embossing apparatus is passed about the inner periphery of theroll 40, is wrapped about the upper periphery of the roll 38 and then ispassed downwardly about the inner periphery of the roll 36. As the sheetmaterial 10 passes over the periphery of the roll 38, the carbon guideblocks 88 are guided along the triangular ribs 12 in the side marginalportions thereof, and the cutting blades 94 incise the sheet material 10adjacent the semicircular ribs 14 along both side marginal portions ofthe material.'The trimmed sheet material 120 and the scrap material 122from the side margins thereof both pass about the roll 36, and thetrimmed sheet material 120 is guided by the guide rolls 124 to a rollwinder (not shown). The scrap material 122 from both side margins isguided by the guide rolls 126 for collection in apparatus (not shown).

As will be readily appreciated, the slides 64, 66 may be moved up anddown by rotation of the handle 70 in order to compensate for significantchanges in the thickness of the embossed sheet material 10. However, thebiasing pressure of the spring 98 and the adjustment provided for thelength of the bolt 100 affords compensation for the normal range ofdeviations in thickness occurring during operation of the apparatus witha sheet material of a preselected thickness.

As the sheet material 10 tends to displace axially along the surface ofthe roll 38 during normal operation of the apparatus, the guide blocks88 will be moved axially therewith as a result of the engagement of theribs 12 in the grooves 96 thereof. The slide blocks 50, 52 will permitthis movement since they are slidably supported on the shafts 46, 48. Ifthe ple, a vibrating cutter, or a vibrator operated shears or a hot wirecutter all may be employed if so desired. In practice, it has been foundthat the illustrated cutting blade has been highly efficient and avoidspossible mechanical difficulties with more complex structures.

In the illustrated embodiment, the roll assembly is employed to providea support surface for the sheet material at the cutting station and tomaintain the sheet material in firm surface contact at the point ofcutting while eliminating any possible buckling across the width of theweb. It can be seen that the sheet material is threaded through thetriangularly disposed set of rolls so that it wraps about the cuttingroll through an angle of approximately 180. Thus, the sheet materiallies straight in the axis of the roll and does not buckle across thewidth thereof since it is held firmly against the surface. However,alternative means may be substituted for the roll assembly such as a bedplate with suitable pressure plates or rollers holding the sheetmaterial firmly against the surface thereof. Where a cutting blade isemployed, or where the cutting means requires a portion extending belowthe surface of the sheet material, the support surface should beprovided with a groove or other recess to receive that portion of thecutting member. This will minimize wear and any possibility that thesheet material will be distorted or displaced thereby.

If it is necessary that only one edge of the sheet material be trimmed,it will be appreciated that the illustrated apparatus may be modified soas to omit one of the guide blocks 88 and the supports and otherelements therefor. Although it is possible to link the two guide blockstogether for simultaneous movement thereof to precisely control thewidth of the sheet material, generally it is desirable to allow theseelements to track independently inorder to ensure optimum edge alinementwith the pattern of embossments despite minor deviations in width.

The guide blocks are desirably formed from a material which isrelatively readily abradable such as carbon block or cake graphite orplastic. In this manner, the guide blocks may have their operatingsurface formed with the grooves in precise alinement with the pattern ofribs formed by a given embossing roll. More particularly, a carbon blockor the like is first provided with an arcuate surface of a radiuscooperating with that of the roll. The block is ground or lapped by useof lapping compound therebetween and relative movement between the sheetmaterial and the block. The lapping com-.

pound on the surfaces of the ribs will cause the material of the guideblock to wear away and produce the grooves in precise registry with theribs in the reference sheet material. This can conveniently be done onthe apparatus per se during startup of the run utilizing the firstportion of the sheet material produced.

The configuration of the ribs and of the embossments may vary dependingupon the.intended application. For example, the ribs may have arectangular cross section or some other form of polygonal cross section.The embossments in the body portion of the sheet material may beparabolic in cross section or they may be, infact, semispherical orportions of a parabola arranged in some pattern across the width of thesheet material. Although generally the sheet material will be incisedbetween the guiding ribs and the pattern of embossments, for someapplications it may be desired to leave a portion of the ribs on thetrimmed sheet material. Although it is possible to have but one rib inthe side marginal portion for cooperation with the guide block,generally at least two and preferably 'a multiplicity of such ribs areutilized to ensure proper alinement and operation.

Thus, it can be seen that the present invention provides a method fortrimming sheet materialin the side marginal portions thereof to provideside edges which are in predetermined alinement with the embossments inthe principal portion thereof. The method and the apparatus therefor arereadily adapted to deviation in thewidth of the sheet material andaccommodate displacement of the sheet material axially along the surfaceof the support roll. Deviations in thickness of the sheet materialproduced'by pulsation in the extruder or irregularities in the embossingoperation do not detract from the firm surface contact between the guideblock and the sheet material so that trouble-free operation is readilyattainable.

I claim:

1. In apparatus for trimming embossed sheet material to provide at leastone side edge of predetermined alinement with respect to theembossments, the combination comprising; a member providing a supportsurface for sheet material passing thereby; guide member support means;means mounting said guide member support means for movement relative tosaid support surface transversely of the direction of travel of thesheet material thereby; and a guide member on said guide member supportmeans overlying said support surface and having at least one groovetherein adapted to receive a longitudinally extending rib on the sheetmaterial passing over said support surface, said guide membercontrolling cutting means for cutting the sheet material at apredetermined location across the width thereof relative to said groove,whereby said guide member support means may move relative to saidsupport surface in response to displacement of the sheet materialrelative to said support surface transversely of the direction of travelof the sheet material thereby.

2. The apparatus in accordance with claim wherein said member providinga support surface is a rotata'bly mounted cutting roll in a rollassembly providing for passage of the sheet material about a substantialportion of the periphery of said cutting roll.

3. The apparatus in accordance with claim 2 wherein said cutting rollhas a circumferential groove therein and therein said cutting means is ablade member incising the sheet material and extending into said groove.

4. The apparatus in accordance with claim 1 wherein a pair of guidemembers are supported in spaced relationship overlying said supportsurface and control cutting means for cutting the sheet material alongboth side marginal portions thereof.

5. The apparatus in accordance with claim 1 wherein said combinationincludes means of biasing said guide member towards said supportsurface.

6. The apparatus in accordance with claim 5 wherein said I biasing meansis adjustable to provided a predetermined amount of pressure on thesheet material and resultant resistance to deflection as a result ofdeviation in the thickness thereof. I

7. The apparatus in accordance with claim 1 wherein said cutting meansis a cutting blade and wherein said support surface has a recess thereininto which said cutting blade extends.

8. The apparatus in accordance with claim 1 wherein said mounting meansincludes a shaft extending transversely of the direction of travel ofthe sheet material and a member slidably mounted thereon to provide thesupport for said guide member.

9. The apparatus in accordance with claim 1 wherein said mounting meansincludes a pair of vertically spaced shafts extending trans'verselyofthe direction of travel of the sheet material and a member slidablysupported on each of said shafts, and wherein said guide member supportmeans includes a connecting link assembly and a relatively rigid guidearm spaced above said connecting link assembly, the guide member beingpivotably supported by said connecting link assembly and adjustablycoupled to said guide arm.

10. The apparatus in accordance with claim 9 wherein the portion of themounting means coupling said guide block to said guide arm comprises abolt member and a spring thereabout biasing said guide member towardssaid support 1 surface, the length of the bolt member between said guidearm groove therein receiving said cutting means.

12. The apparatus-in accordance with claim 9 wherein said slidablysupported members carry a slide assembly, the slidable element thereofbeing slidable in a vertical plane to promote adjustment of the verticalspacing between said guide member and said support surface.

13. The apparatus in accordance with claim 2 wherein said memberproviding a support surface is a cutting roll in a roll assembly andwherein means are provided for adjusting said roll axially in adirection transverse to the direction of travel of the sheet material,said cutting roll having a circumferential 14. In apparatus for trimmingembossed sheet material to provide at least one side edge ofpredetermined alinement with respect to the embossments, the combinationcomprising; a roll assembly including a cutting roll and providing forpassage of the sheet material about a substantial portion of theperiphery of said cutting roll; guide member support means; meansmounting said guide member support means for movement relative to saidcutting roll transversely of the direction of travel of the sheetmaterial thereby, said mounting means including a shaft extendingparallel to the-axis of said cutting roll and a member slidably mountedthereon providing the support for said member support means; a guidemember on said guide member support means overlying said cutting rolland having at least one groove therein adapted to receive alongitudinally extending rib on the sheet material passing about saidcutting roll, said guide member controlling cutting means for cuttingthe sheet material at a predetermined location across the width thereofrelative to said groove; and means biasing said guide member towardssaid cutting roll, whereby said guide member support means may moveaxially relative to said cutting roll in response to displacement of thesheet material axially relative to said cutting roll transversely of thedirection of travel of the sheet material thereby.

15. The apparatus in accordance with claim 14 wherein said cutting rollhas a circumferential groove therein and wherein said cutting means is ablade member incising the sheet material and extending into said groove.

16. The apparatusin accordance with claim 14 wherein a pair of guidemembers are supported in spaced relationship overlying said supportsurface and control cutting means for cutting the sheet material alongboth side marginal portions thereof.

17. The apparatus in accordance with claim 14 wherein said biasing meansis adjustable to provide a predetermined amount of pressure on the sheetmaterial and resultant resistance to deflection as a result of deviationin the thickness thereof.

18. The apparatus in accordance with claim 14 wherein said mountingmeans includes a pair of vertically spaced shafts extending transverselyof the direction of travel of the sheet material and a member slidablysupported on each of said shafts, and wherein said guide member supportmeans includes a connecting link assembly and a relatively rigid guidearm spaced above said connecting link assembly, the guide member beingpivotably supported by said connecting link assembly and adjustablycoupled to said guide arm.

19. The apparatus in accordance with claim 18 wherein the portion of themounting means coupling said guide block to said guide arm comprises abolt member and a spring thereabout biasing said guide member towardssaid support surface, the length of the bolt member between said guidearm and guide member being adjustable to vary the preloading of saidspring.

20. The apparatus in accordance with claim 14 wherein said slidablysupported member carries a slide assembly; the slidable element thereofbeing slidable in a vertical plane to promote adjustment of the verticalspacing between said guide member and said cutting roll.

21. The apparatus in accordance with claim 15 wherein said roll assemblyprovides means for adjusting said cutting roll axially to maintain saidgroove therein in alinement with said blade member.

